Aspects of Optical Coherence Tomography (OCT) in Healthy Eyes and Eyes with Retinal Diseases

Sammanfattning: Optical coherence tomography (OCT) is a technique in which cross-sectional images from intraocular tissue can be obtained. The quantitative and qualitative examinations are used for evaluating retinal diseases. Conventional OCT (Stratus) is mainly used, but the new Spectral domain (Cirrus) OCT, which has improved technology, may provide more reliable measurements.The aim of the study was to collect normal values of macular thickness in children and adults and to evaluate the effect of age and/or gender, to compare measurement variability in healthy eyes and eyes with age-related macular degeneration (AMD), to compare Stratus and Cirrus OCT and to study the effect of cataract surgery on macula.Sixty-seven healthy adults and 56 children, 30 patients with AMD, 34 patients with diabetes and cataract and 35 healthy controls were included. The quantitative maps in Stratus and Cirrus were used and manual correction of foveal location was evaluated. Qualitative OCT was compared to fluorescein angiography (FA) after cataract surgery.The mean values of macular thickness in Stratus OCT were 207µm in adults and 204 µm in children. The measurement variability was low. Macular thickness decreased with age in adults, but not in children. No correlation with gender was found. In eyes with wet AMD, there were small differences in measurement variability comparing Stratus and Cirrus OCT. After manual correction in Cirrus OCT, the coefficients of repeatability were improved to values close to the repeatability in normal eyes. Two thirds of the diabetic and half of the control eyes showed leakage on FA after cataract surgery. Qualitative OCT corresponded poorly to FA in diabetic eyes. A thicker macula, assessed with OCT, was often observed without any obvious effect on visual acuity.  OCT was as good as FA in revealing clinically relevant changes in macula after surgery, and was the technique recommended for follow-up.